Evaluation of flash echo imaging of the canine gastrointestinal tract.

Although it is important to assess gastrointestinal blood flow, no generally useful, noninvasive assessment method has been established. Harmonic flash echo imaging, which is an intermittent second harmonic imaging technique, has recently become available to evaluate blood flow. We investigated the usefulness of harmonic flash echo imaging in the assessment of the gastrointestinal tract, and we used this technique to study the effect of nicotine on small bowel blood flow. Harmonic flash echo imaging was performed at the beginning of intravenous injection of a contrast agent. It was also performed on the small bowel immediately before and 10 min after nicotine administration to evaluate blood flow. Gastric and small bowel walls were clearly enhanced on the primary images. Small bowel enhancement, which is regarded as transmural blood flow, significantly decreased after nicotine administration. Harmonic flash echo imaging appears to be useful in the assessment of the transmural blood flow in the gastrointestinal wall.